|  | 7.1 | Cisco Routers in NetWare Networks
| 7.1.3 | IPX Addressing

Novell IPX addressing uses a two-part address-the network number and the node number. The node number is usually the Media Access Control (MAC) address for a network interface in the end node. Novell IPX supports multiple logical networks on an individual interface; each network requires a single encapsulation type. The IPX network number, which is assigned by the network administrator, can be up to eight base 16 (hexadecimal) digits in length. Figure shows two IPX networks, 4a1d and 3f. The IPX node number is 12 hexadecimal digits in length. This number is usually the MAC address, obtained from a network interface that has a MAC address. The use of the MAC address in the logical IPX address eliminates the need for Address Resolution Protocol (ARP). Serial interfaces use the MAC address of the Ethernet interface for their IPX node address. The Figure shows the IPX node 0000.0c56.de33 on the 4a1d network. Another node address is 0000.0c56.de34 on the 3f network. Regardless of whether you're using a LAN or a WAN interface, you assign the same IPX network numbers to the routers that are in use by the IPX devices. The best and recommended way to obtain a Novell network address is to ask the network administrator for one. The network administrator must specify the correct IPX network address on the Cisco router for the same network where you want to have IPX enabled. If you cannot obtain an IPX address from the network administrator, you can get the IPX address directly from a neighbor router. To do this, you Telnet to the neighbor router and use the show protocols or show ipx interface command.
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The show ipx interface Command

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Washington Project: IPX Addressing Issues

When planning IPX addressing, you do not need to worry about numbering hosts as you would for TCP/IP. This is because the host address for a workstation is usually the MAC address of that station's network interface card. However, you need to develop a scheme for the IPX network numbers in the Washington School District WAN. Remember that a router can't have two interfaces that belong to the same logical (IP, IPX, and so on) network, or subnet; therefore, you cannot use the same network number throughout the district WAN.

When you develop your IPX network numbering scheme, keep in mind that IPX network numbers can be up to 32 bits (or 8 hexadecimal digits), but they usually contain leading zeros to "pad out" the address. For example, the number 21 can be used as a valid IPX network number because leading zeros can be added to expand 21 into 32 bits (written as 8 hexadecimal digits): 00000021.

Some network administrators convert the IP network address to hexadecimal and use the result as the IPX network number. For example, the subnet 169.199.69.128 /27 would become A9C74580. But, there's no rule that says you have do this. You can use the leading zeros feature to create very simple IPX network numbers (such as 10, 20, 30, and so on).

You will see later in this chapter that, because of Layer 2 issues, a router interface may need to exist on two logical networks-that is, have two network numbers simultaneously. After you have read about Novell frame encapsulation types, you should check the TCS Overview carefully to see if your addressing scheme needs to account for this.

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